Observational infant exploratory [(14)C]-paracetamol pharmacokinetic microdose/therapeutic dose study with accelerator mass spectrometry bioanalysis

AIMS

The aims of the study were to compare [(14)C]-paracetamol ([(14)C]-PARA) paediatric pharmacokinetics (PK) after administration mixed in a therapeutic dose or an isolated microdose and to develop further and validate accelerator mass spectrometry (AMS) bioanalysis in the 0-2 year old age group.

METHODS

[(14)C]-PARA concentrations in 10-15 µl plasma samples were measured after enteral or i.v. administration of a single [(14)C]-PARA microdose or mixed in with therapeutic dose in infants receiving PARA as part of their therapeutic regimen.

RESULTS

Thirty-four infants were included in the PARA PK analysis for this study: oral microdose (n = 4), i.v. microdose (n = 6), oral therapeutic (n = 6) and i.v. therapeutic (n = 18). The respective mean clearance (CL) values (SDs in parentheses) for these dosed groups were 1.46 (1.00) l h(-1), 1.76 (1.07) l h(-1), 2.93 (2.08) l h(-1) and 2.72 (3.10) l h(-1), t(1/2) values 2.65 h, 2.55 h, 8.36 h and 7.16 h and dose normalized AUC(0-t) (mg l(-1) h) values were 0.90 (0.43), 0.84 (0.57), 0.7 (0.79) and 0.54 (0.26).

CONCLUSIONS

All necessary ethical, scientific, clinical and regulatory procedures were put in place to conduct PK studies using enteral and systemic microdosing in two European centres. The pharmacokinetics of a therapeutic dose (mg kg(-1)) and a microdose (ng kg(-1)) in babies between 35 to 127 weeks post-menstrual age. [(14)C]-PARA pharmacokinetic parameters were within a two-fold range after a therapeutic dose or a microdose. Exploratory studies using doses significantly less than therapeutic doses may offer ethical and safety advantages with increased bionalytical sensitivity in selected exploratory paediatric pharmacokinetic studies.

Fabrication of electrochemical sensor for paracetamol based on multi-walled carbon nanotubes and chitosan-copper complex by self-assembly technique

An electrochemical sensor for paracetamol based on multi-walled carbon nanotubes and chitosan-copper complex (MWCNTs/CTS-Cu) was fabricated by self-assembly technique. The MWCNTs/CTS-Cu modified GCE showed an excellent electrocatalytic activity for the oxidation of paracetamol, and accelerated electron transfer between the electrode and paracetamol. Under optimal experimental conditions, the differential pulse peak current was linear with the concentration of paracetamol in the range of 0.1-200 μmol L(-1) with a detection limit of 0.024 μmol L(-1). The sensitivity was found to be 0.603 A/mol L(-1). The proposed sensor also showed a high selectivity for paracetamol in the presence of ascorbic acid and dopamine. Moreover, the proposed electrode revealed good reproducibility and stability. The proposed method was successfully applied for the determination of paracetamol in tablet and human serum samples.

[Determination of serum acetaminophen based on the diazo reaction and its application in the evaluation of gastric emptying]

This study aims to establish a method to determine the serum acetaminophen concentration based on diazo reaction, and apply it in the gastric emptying evaluation. Theoretically, acetaminophen could take hydrolysis reaction in hydrochloric acid solution to produce p-aminophenol, which could then take diazo reaction resulting in a product with special absorption peak at 312 nm. Then the serum acetaminophen concentration and recovery rate were calculated according to the standard curve drawn with absorbance at 312 nm. ICR mice were given a dose of acetaminophen (500 mg x kg(-1)) by gavage and the serum acetaminophen was dynamically measured through the diazo reaction. Besides, ICR mice were subcutaneously injected with the long-acting GLP-1 analog GW002 before the gavage of acetaminophen, and serum acetaminophen concentration was measured as above to study how GW002 could influence the gastric emptying. The data showed acetaminophen ranging from 0 to 160 μg x mL(-1) could take diazo reaction with excellent linear relationship, and the regression equation was y = 0.0181 x +0.0104, R2 = 0.9997. The serum acetaminophen was also measured with good linear relationship (y = 0.0045 x + 0.0462, R = 0.9982) and the recovery rate was 97.4%-116.7%. The serum concentration of acetaminophen reached peak at about 0.5 h after gavage, and then gradually decreased. GW002 could significantly lower the serum acetaminophen concentration and make the area under the concentration-time curve (AUC) decrease by 28.4%. In conclusion, a method for the determination of serum acetaminophen based on the diazo reaction was established with good accuracy and could be used in the evaluation of gastric emptying.

Recommendations for the paracetamol treatment nomogram and side effects of N-acetylcysteine

Treatment of paracetamol intoxication consists of administration of N-acetylcysteine, preferably shortly after paracetamol ingestion. In most countries, the decision to treat patients with N-acetylcysteine depends on the paracetamol plasma concentration. In the literature, different arguments are given regarding when to treat paracetamol overdose. Some authors do not recommend treatment with N-acetylcysteine at low paracetamol plasma concentrations since unnecessary adverse effects may be induced. But no treatment with N-acetylcysteine at higher paracetamol plasma concentrations may lead to unnecessary severe morbidity and mortality. In this review, we provide an overview on the severity and prevalence of adverse side effects after N-acetylcysteine administration and the consequences these side effects may have for the treatment of paracetamol intoxication. The final conclusion is to continue using the guidelines of the Dutch National Poisons Information Centre for N-acetylcysteine administration in paracetamol intoxication.

Interaction between different extracts of Hypericum perforatum L. from Serbia and pentobarbital, diazepam and paracetamol

Herb-drug interactions are an important safety concern and this study was conducted regarding the interaction between the natural top-selling antidepressant remedy Hypericum perforatum (Hypericaceae) and conventional drugs. This study examined the influence of acute pretreatment with different extracts of Hypericum perforatum from Serbia on pentobarbital-induced sleeping time, impairment of motor coordination caused by diazepam and paracetamol pharmacokinetics in mice. Ethanolic extract, aqueous extract, infusion, tablet and capsule of Hypericum perforatum were used in this experiment. The profile of Hypericum perforatum extracts as well as paracetamol plasma concentration was determined using RP-HPLC analysis. By quantitative HPLC analysis of active principles, it has been proven that Hypericum perforatum ethanolic extract has the largest content of naphtodianthrones: hypericin (57.77 µg/mL) and pseudohypericin (155.38 µg/mL). Pretreatment with ethanolic extract of Hypericum perforatum potentiated the hypnotic effect of pentobarbital and impairment of motor coordination caused by diazepam to the greatest extent and also increased paracetamol plasma concentration in comparison to the control group. These results were in correlation with naphtodianthrone concentrations. The obtained results have shown a considerable influence of Hypericum perforatum on pentobarbital and diazepam pharmacodynamics and paracetamol pharmacokinetics.

Influence of laxatives on gastric emptying in healthy warmblood horses evaluated with the acetaminophen absorption test

The use of laxatives is crucial in the treatment of horses with caecal or large colon impaction.To reach the large intestinal contents and resolve the impaction, laxatives must leave the stomach and pass through the small intestine.The aim of this study was to prove whether isotonic solutions of saline cathartics do not affect gastric emptying rate in contrast to hypertonic solutions. Six, fasted, healthy, adult Warmblood horses were used in a randomized study design with 1.8% sodium sulfate (1.8% Na2SO4), 4.2% magnesium sulfate (4.2% MgSO4), 25% sodium sulfate (25% Na2SO4), 25% magnesium sulfate (25% MgSO4) and water at either 20 ml/kg BW (Water 20) or 4 ml/kg BW (Water 4), administered via nasogastric intubation. For indirect measurement of liquid-phase gastric emptying, the liquid-phase passage marker acetaminophen (20 mg/kg BW in 200 ml water) was added to each trial. Serum samples were collected at predetermined time points for pharmacokinetic analysis. The time to reach maximum serum concentration (Tmax) was considered as gastric emptying rate. Compared to Water 4, Tmax of 25% Na2SO4 and 25% MgSO4 was reached significantly later, the maximum serum concentration (Cmax) of acetaminophen was significantly lower and the area under the curve determined up to 90 min (AUC90) was significantly smaller. Isotonic solutions of saline cathartics (1.8% Na2SO4, 4.2% MgSO4) did not influence the gastric emptying rate. Hypertonic solutions of saline cathartics (25% Na2SO4, 25% MgSO4) significantly delayed the gastric emptying rate.

Facile and novel electrochemical preparation of a graphene-transition metal oxide nanocomposite for ultrasensitive electrochemical sensing of acetaminophen and phenacetin

A facile and novel preparation strategy based on electrochemical techniques for the fabrication of electrodeposited graphene (EGR) and zinc oxide (ZnO) nanocomposite was developed. The morphology and structure of the EGR-based nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (XPS) and Raman spectroscopy. Meanwhile, the electrochemical performance of the nanocomposite was demonstrated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effect of EGR and ZnO nanoparticles, an ultrasensitive electrochemical sensor for acetaminophen (AC) and phenacetin (PCT) was successfully fabricated. The linearity ranged from 0.02 to 10 μM for AC and 0.06 to 10 μM for PCT with high sensitivities of 54,295.82 μA mM(-1) cm(2) for AC and 21,344.66 μA mM(-1) cm(2) for PCT, respectively. Moreover, the practical applicability was validated to be reliable and desirable in pharmaceutical detections. The excellent results showed the promise of the proposed preparation strategy of EGR-transition metal oxide nanocomposite in the field of electroanalytical chemistry.

Effect of spiramycin and tulathromycin on abomasal emptying rate in milk-fed calves

Impaired abomasal motility is common in cattle with abomasal disorders. The macrolide erythromycin has been demonstrated to be an effective prokinetic agent in healthy calves and in adult cattle with abomasal volvulus or left displaced abomasum. We hypothesized that 2 structurally related macrolides, spiramycin and tulathromycin, would also be effective prokinetic agents in cattle. Six milk-fed, male, Holstein-Friesian calves were administered each of the following 4 treatments: spiramycin, 75 000 IU/kg BW, IM, this dose approximates 25 mg/kg BW, IM; tulathromycin, 2.5 mg/kg BW, SC; 2 mL of 0.9% NaCl (negative control); and erythromycin, 8.8 mg/kg BW, IM (positive control). Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 min after each treatment was administered and jugular venous blood samples were obtained periodically after the start of sucking. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Spiramycin, tulathromycin, and the positive control erythromycin increased abomasal emptying rate compared to the negative control. We conclude that the labeled antimicrobial dose of spiramycin and tulathromycin increases the abomasal emptying rate in healthy milk-fed calves. Additional studies investigating whether spiramycin and tulathromycin exert a prokinetic effect in adult cattle with abomasal hypomotility appear indicated.

Weight, pregnancy and oral contraceptives affect intravenous paracetamol clearance in young women

OBJECTIVES

Because of the extensive variability in paracetamol clearance in young women, published data were pooled with newly collected observations in search of covariates of paracetamol pharmacokinetics (PK) within this specific population.

SUBJECTS AND METHODS

PK estimates and clinical characteristics [pregnant, weight, exposure to oral contraceptives (OC)] in young women following IV loading dose (2 g paracetamol) were pooled, using a non-compartmental linear disposition model in individual time-concentration profiles. Data were reported by median and range. Rank correlation was used to link clearance (l/h) to weight, Mann Whitney U test to compare clearance (l/h.m-2) between subgroups (pregnant, OC exposure). Finally, a multiple regression model with clearance (l/h) in all women and all non-pregnant women was performed.

RESULTS

Based on 73 paracetamol PK estimates, a 8-fold variability in clearance (range 7.1-62.2 l/h) was documented, in part explained by a correlation (r2=0.36) between clearance (l/h) and weight. Clearance (l/h and l/h.m-2) and distribution volume (l) at delivery (n=36) were higher compared to non-pregnant observations. In non-pregnant women, women on OC (n=20) had a higher paracetamol clearance (l/h.m-2) compared to women (n=17) not on OC (p = 0.023). Weight (p = 0.0043) and pregnancy (p = 0.02) were independent variables (r=0.56) of paracetamol clearance (l/h). In non-pregnant women, weight (p = 0.009) and OC exposure (p = 0.03) were independent variables (r=0.51).

CONCLUSIONS

Weight, pregnancy and OC result in higher clearance of IV paracetamol in young women. Besides compound specific relevance, these findings also unveil covariates of drug metabolism in young women.

Turpentine oil induced inflammation decreases absorption and increases distribution of phenacetin without altering its elimination process in rats

Plasma concentrations and pharmacokinetics of phenacetin, a CYP1A2 substrate were determined in normal and experimentally induced inflamed rats by turpentine oil to know the role of inflammation on the pharmacokinetics of phenacetin and formation of its active metabolite (paracetamol) by CYP1A2 in wistar albino rats, weighing about 200-250 g that were randomly divided into two groups consisting six in each group. Rats in group I (control) received phenacetin (150 mg kg(-1), PO) where as group II received phenacetin 12 h after induction of inflammation by turpentine oil (0.4 mL, i.m). Blood samples were collected from retro orbital plexus at pre-determined time intervals prior to and at 0.166, 0.33, 0.67, 1.5, 2, 4, 8 and 12 h post-administration of phenacetin. Plasma was separated and analyzed for phenacetin and its metabolite paracetamol by HPLC assay. Based on plasma concentrations of phenacetin and its metabolite paracetamol, the pharmacokinetic parameters were determined by compartmental methods. C(max) of phenacetin was significantly (p < 0.01) decreased to 19.50 ± 2.74 μg mL(-1) in inflamed conditions compared to 38.13 ± 2.20 μg mL(-1) obtained in normal rats. Except, for significant (p < 0.001) increase in volume of distribution at steady state (V(dss)) from 2.87 ± 0.37 to 8.03 ± 1.26 L kg(-1) and increased the rate of absorption with shorter absorption half-life (t(1/2ka)) for phenacetin in inflammation. None of the pharmacokinetic parameters of either phenacetin or its metabolite paracetamol were affected. It can be concluded that turpentine oil induced inflammation has no role on the activity of CYP1A2 in rats, as the plasma concentrations and pharmacokinetic parameters of paracetamol were found unaltered.

Pattern recognition analysis for hepatotoxicity induced by acetaminophen using plasma and urinary 1H NMR-based metabolomics in humans

Drug-induced liver injury (DILI) is currently an increasingly relevant health issue. However, available biomarkers do not reliably detect or quantify DILI risk. Therefore, the purpose of this study was to comparatively evaluate plasma and urinary biomarkers obtained from humans treated with acetaminophen (APAP) using a metabolomics approach and a proton nuclear magnetic resonance (NMR) platform. APAP (3 g/day, two 500 mg tablets every 8 h) was administered to 20 healthy Korean males (age, 20-29 years) for 7 days. Urine was collected daily before and during dosing and 6 days after the final dose. NMR spectra of these urine samples were analyzed using principal component analysis (PCA) and partial least-squares-discrimination analysis. Although the activities of aspartate aminotransferase and lactate dehydrogenase were significantly increased 7 days post-APAP treatment, serum biochemical parameters of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, γ-glutamyl transpeptidase, and lactate dehydrogenase were within normal range of hepatic function. However, urine and plasma (1)H NMR spectroscopy revealed different clustering between predosing and after APAP treatment for global metabolomic profiling through PCA. Urinary endogenous metabolites of trimethylamine-N-oxide, citrate, 3-chlorotyrosine, phenylalanine, glycine, hippurate, and glutarate as well as plasma endogenous metabolites such as lactate, glucose, 3-hydroxyisovalerate, isoleucine, acetylglycine, acetone, acetate, glutamine, ethanol, and isobutyrate responded significantly to APAP dosing in humans. Urinary and plasma endogenous metabolites were more sensitive than serum biochemical parameters. These results might be applied to predict or screen potential hepatotoxicity caused by other drugs using urinary and plasma (1)H NMR analyses.

Possible fatal acetaminophen intoxication with atypical clinical presentation

Acetaminophen or paracetamol, a commonly used over-the-counter analgesic, is known to elicit severe adverse reactions when taken in overdose, chronically at therapeutic dosage or, sporadically, following single assumptions of a therapeutic dose. Damage patterns including liver damage and, rarely, acute tubular necrosis or a fixed drug exanthema. We present a case of fatal acetaminophen toxicity with postmortem blood concentration 78 μg/mL and unusual clinical features, including a visually striking and massive epidermolysis and rhabdomyolysis, disseminated intravascular coagulation and myocardial ischemia. This case is compared with the most similar previous reports in terms of organ damage, clinical presentation, and cause of death. We conclude that a number of severe patterns of adverse effects to acetaminophen are emerging that were previously greatly underestimated, thus questioning the adequacy of the clinical spectrum traditionally associated with acetaminophen intoxication and leading to the need to review this spectrum and the associated diagnostic criteria.

Metabolism and disposition of acetaminophen: recent advances in relation to hepatotoxicity and diagnosis

Acetaminophen (APAP) is one of the most widely used drugs. Though safe at therapeutic doses, overdose causes mitochondrial dysfunction and centrilobular necrosis in the liver. The first studies of APAP metabolism and activation were published more than 40 years ago. Most of the drug is eliminated by glucuronidation and sulfation. These reactions are catalyzed by UDP-glucuronosyltransferases (UGT1A1 and 1A6) and sulfotransferases (SULT1A1, 1A3/4, and 1E1), respectively. However, some is converted by CYP2E1 and other cytochrome P450 enzymes to a reactive intermediate that can bind to sulfhydryl groups. The metabolite can deplete liver glutathione (GSH) and modify cellular proteins. GSH binding occurs spontaneously, but may also involve GSH-S-transferases. Protein binding leads to oxidative stress and mitochondrial damage. The glucuronide, sulfate, and GSH conjugates are excreted by transporters in the canalicular (Mrp2 and Bcrp) and basolateral (Mrp3 and Mrp4) hepatocyte membranes. Conditions that interfere with metabolism and metabolic activation can alter the hepatotoxicity of the drug. Recent data providing novel insights into these processes, particularly in humans, are reviewed in the context of earlier work, and the effects of altered metabolism and reactive metabolite formation are discussed. Recent advances in the diagnostic use of serum adducts are covered.

[Intoxication or false-positive acetaminophen result of toxicological determinations? Two case reports]

The aim of this study was to show the diagnostic procedure used in the two cases with false-positive serum acetaminophen results in suspected acetaminophen poisoning. The determination of serum acetaminophen were carried out using a UV/VIS spectrophotometer (Specord 40 Analytik Jena), coupled with an analytic computer station WinASPECT. The employed method of determination was based on the acetaminophen reaction with sodium nitrite, which yields yellow colour of solution in the presence of sodium hydrate. The intensity of the yellow colour depends on the concentration of acetaminophen in serum. The relationship between absorbance and concentration was linear at concentrations in the range 50-600 microg/mL, with relative standard deviation of +/- 2.1% and detection limit of 30 microg/mL. To confirm or reject the doubtful results of colorimetric assays, the serums of patients were measured with high performance liquid chromatography with mass spectrometry detection and gas chromatography with mass spectrometry detection. The analysis of presented cases leads to a conclusion that acetaminophen results should be confirmed either by scanning urine for p-aminophenol presence (which is a routine procedure in our laboratory) or by using a different method of measuring acetaminophen serum levels.

The impaired disposition of probe drugs is due to both liver and kidney dysfunctions in CCl(4)-model rats

The carbon tetrachloride (CCl(4))-treated model involving mature Sprague-Dawley rats has been historically relied upon to study liver injury and regeneration and to test drug efficacy and disposition. However, there few studies about phase II metabolic enzymes changes in CCl(4)-model rats. The metabolic and excretion tests of phenacetin and acetaminophen (APAP), and the mRNA test of cytochrome P4501A2 (CYP1A2) and phase II metabolic enzymes [sulfotransferase 1A1 (SULT1A1) and UDP-glucuronosyltransferase 1A6 (UGT1A6)] were studied in model rats after CCl(4) pretreatment. The result showed that the function and structure of liver and kidney was impaired by CCl(4) pretreatment, and a significant difference has been observed in the mRNA content of CYP1A2 (p<0.01) in model group, but there was no significant difference on the mRNA content of SULT1A1 and UGT1A6 in both groups. Compared to the control group, a significant higher content of phenacetin (p<0.01) and sulfate-APAP (AS, p<0.01) was observed in the metabolic tests of phenacetin and APAP. Statistically significant differences in cumulative urinary excretion levels of APAP, AG and AS for CCl(4) model rats were observed also. We have shown that impaired disposition of probe drugs in this model was due to both liver and kidney dysfunction in CCl(4)-model rats and we should consider the development of a new liver damage model without renal impairment.

Perforated dried blood spot accurate microsampling: the concept and its applications in toxicokinetic sample collection

Dried blood spot (DBS) sampling has gained considerable interest as a microsampling technique to support drug discovery and development owing to its enormous ethical and practical benefits. Quantitative determinations of drugs and/or their metabolites collected in DBS matrix in its current format, however, have encountered technical challenges and regulatory uncertainty. The challenges of DBS bioanalysis are largely ascribed to the way how samples are collected and analyzed. Currently, an uncontrolled amount of a blood sample, e.g. 20 µl, is collected per time point per sample and spotted onto cellulose paper. Quantitation is based on removal of a fixed area of the DBS sample, resulting in sample waste, a need for mechanical punching and concomitant potential punching carryover, uncertainty in recovery assessment and the adverse impact of hematocrit on accurate quantitation. Here, we describe the concept and applications of a novel concept, namely perforated dried blood spot (PDBS), for accurate microsampling that addresses previous challenges. Advantages of PDBS are enumerated and compared with conventional DBS in the context of microsampling and liquid chromatography tandem mass spectrometry bioanalysis. Two approaches for accurate microsampling of a small volume of blood (5 µl) are proposed and demonstrated, i.e. Microsafe® pipettes and the Drummond incremental pipette. Two online sample enrichment techniques to enhance liquid chromatography tandem mass spectrometry sensitivity for microsampling bioanalysis are discussed. The PDBS concept was successfully applied for accurate sample collection (5 µl) in a toxicokinetic study in rats given a single oral gavage dose of acetaminophen. Perspectives on bioanalytical method validation for regulated DBS/PDBS microsampling are also presented.

[Study on the effect using hemoperfusion to treat tylenol poisoned patients]

OBJECTIVE

To explore the effect of hemoperfusion (HP) on tylenol poisoned patients.

METHODS

Urgently established the blood access by transfemoral catheterization of femoral vein, we used charcoal hemoperfusion by blood pump and dynamically monitored the plasma concentration of tylenol active ingredients for the 2 patients and the content of tylenol active ingredients in the charcoal was determined.

RESULTS

Plasma concentration of tylenol active ingredients of the 2 patients was declined gradually during and after the HP management. The acetaminophen serum concentration of the case 1 was declined from the 13.4 µg/L at the start of HP to the 5.81 µg/L at the end of HP; and the case 2 was declined from 51.1 µg/L to 22.3 µg/L. The adsorption amount of acetaminophen in the blood perfusion device are respectively 119 542 µg of case 1 and 33 2154 µg of case 2.

CONCLUSION

Early hemoperfusion should be carried out for acute tylenol poisoning patients if there were indications, hemoperfusion can clear the tylenol active ingredients and this is an effective measure to eliminate tylenol active ingredients.

[Study of the serum concentrations of acetaminophen overdose]

Acetaminophen (APAP) is a commonly used nonsteroidal analgesic because it is considered safe. However, APAP is a major cause of acute poisoning because of its easy availability. APAP overdose causes hepatic failure. A previous study reported a case of death occurring 3-4 days after APAP overdose. Serum APAP level is an index for administration of N-acetyl-L-cysteine (NAC). We investigated cases of APAP overdose to determine the correlation between serum APAP level and estimated APAP dosage, NAC medication, hepatic failure, etc. In one case, we found that the use of estimated APAP dosage alone led to inappropriate NAC medication. Moreover, there were cases in which serum APAP level increased 4 hr after APAP overdose. Repeated cases of APAP overdose suggested that the presence of NAC medication caused a difference in liver function test values.

Therapeutic paracetamol treatment in older persons induces dietary and metabolic modifications related to sulfur amino acids

Sulfur amino acids are determinant for the detoxification of paracetamol (N-acetyl-p-aminophenol) through sulfate and glutathione conjugations. Long-term paracetamol treatment is common in the elderly, despite a potential cysteine/glutathione deficiency. Detoxification could occur at the expense of anti-oxidative defenses and whole body protein stores in elderly. We tested how older persons satisfy the extra demand in sulfur amino acids induced by long-term paracetamol treatment, focusing on metabolic and nutritional aspects. Effects of 3 g/day paracetamol for 14 days on fasting blood glutathione, plasma amino acids and sulfate, urinary paracetamol metabolites, and urinary metabolomic were studied in independently living older persons (five women, five men, mean (±SEM) age 74 ± 1 years). Dietary intakes were recorded before and at the end of the treatment and ingested sulfur amino acids were evaluated. Fasting blood glutathione, plasma amino acids, and sulfate were unchanged. Urinary nitrogen excretion supported a preservation of whole body proteins, but large-scale urinary metabolomic analysis revealed an oxidation of some sulfur-containing compounds. Dietary protein intake was 13% higher at the end than before paracetamol treatment. Final sulfur amino acid intake reached 37 mg/kg/day. The increase in sulfur amino acid intake corresponded to half of the sulfur excreted in urinary paracetamol conjugates. In conclusion, older persons accommodated to long-term paracetamol treatment by increasing dietary protein intake without any mobilization of body proteins, but with decreased anti-oxidative defenses. The extra demand in sulfur amino acids led to a consumption far above the corresponding population-safe recommendation.

Delayed and prolonged elevated serum paracetamol level after an overdose - possible causes and implications

We report the case of a 29-year-old man who ingested about 50 g of standard-preparation paracetamol plus other medications. The serum paracetamol level remained low in the first 24 hours. It peaked 54 hours after ingestion and remained high for 5 days. An N-acetylcysteine (NAC) infusion was started at admission, but was ceased 36 hours later as the clinical and laboratory signs were reassuring. On Day 3, the patient's liver function deteriorated and a rising serum paracetamol level was noted; hence, an NAC infusion was reinitiated. Despite this, the patient developed fulminant hepatic failure. This case underlines the importance of monitoring paracetamol levels and liver function for at least 72 hours after a suspected large overdose of paracetamol before discontinuing NAC infusion.